Autblog - 2012 Jeep Grand Cherokee SRT8 392 HEMI
07-25-2011, 11:44 AM
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Autblog - 2012 Jeep Grand Cherokee SRT8 392 HEMI Jeep's Best Argument To Skip The Dirt
By Michael Harley
Posted Jul 25th 2011 11:57AM
We've just returned from flogging the all-new 2012 Jeep Grand Cherokee SRT8 on the main 2.5-mile road circuit at Willow Springs Motorsports Park in Southern California. This particular Jeep is nothing like your great-grandfather's ******, your cousin's lifted CJ or even your little sister's Liberty.
Lacking anything close to resembling a Trail Rated badge, this lowered, two-and-a-half ton monster packs a massive 6.4-liter Hemi under its hood, 20-inch forged alloys at each corner and an adaptive damping system to keep body movement in check. Even from a distance, it's hard to miss this four-door's oversized brakes, cannon exhaust pipes and intimidating body cladding. This Jeep looks mean, sounds aggressive and picks fights with sports cars instead of mountains.
But what is the point of the Grand Cherokee SRT8? Do its owners race it, or is this simply an exercise to antagonize cavalier Porsche Cayenne and BMW X5 drivers? What are the benefits – and drawbacks – to packing 470 horsepower in an SUV? Can this thing even tow?
We found answers to all of those questions and more, during our day on the track and long drive back to Los Angeles.
The Jeep Grand Cherokee SRT8 arrived on the scene in 2006 when the automaker dropped a 6.1-liter Hemi under the hood of the previous-generation (WK platform) body. Boasting 425 horsepower and a five-speed automatic transmission, the all-wheel-drive first-generation Grand Cherokee SRT8 was capable of sprinting to 60 miles per hour in the high four-second range and topping out at a redline-limited 170 mph. With twin center-mounted exhaust outlets and five-spoke alloy wheels, the monochromatic SUV had the looks to back up its bark.
Five years later, the fourth-generation Grand Cherokee rides on a new chassis (WK2 platform) shared with the 2012 Mercedes-Benz M-Class. After delivering its latest Trail Rated off-roader with competent but staid 3.6-liter V6 and 5.7-liter V8 powerplants, Jeep offering an SRT version of the Grand Cherokee was inevitable.
Launched at the 2011 New York Auto Show, the second-iteration SRT8 is a vast improvement over its predecessor. According to the automaker, on the tarmac, it's the best performing Jeep vehicle ever, with a 0-60 mph time of 4.8 seconds, a top speed of 160 mph and the ability to stop from 60 mph in just 116 feet.
As mentioned, the Grand Cherokee SRT8 version is unmistakable. Lowered one inch compared to the standard models, the SRT8 wears unique wheel flares, side cladding and a one-piece front fascia with new multi-function LED daytime running lights. The standard hood is replaced with a sculpted unit complete with functional ducts serving as heat extractors for the engine compartment. At the rear, there is a high-mounted liftgate spoiler to reduce drag and aerodynamic lift. A one-piece lower rear diffuser separates the new dual-sport exhaust pipes - while they looked wicked, its predecessor's twin center pipes were a nightmare for those who chose fit a trailer hitch.
The Grand Cherokee SRT8's interior features SRT-styled Nappa leather and suede upholstery, with sculpted bucked seats for the driver and front passenger. Carbon-fiber accents are splashed throughout the instrument panel and door trim, and an all-new heated leather-wrapped steering wheel arrives complete with transmission shift paddles. Jeep's center-mounted Electronic Vehicle Information Center (EVIC) also features performance pages – software that displays instant data about acceleration, horsepower, torque, wheel angle and so on.
Mechanically speaking, Jeep has made a lot of changes to transform its Moab-climbing Grand Cherokee into an asphalt-eating track star.
The hawkish hood hides a 6.4-liter Hemi V8. With a cast-iron block and aluminum-alloy heads, the 90-degree pushrod-operated 16-valve engine has a compression ratio of 10.9:1. Running on premium unleaded fuel, it is rated at 470 horsepower and 465 pound-feet of torque (down five pound-feet when compared to its other SRT8 siblings due to exhaust packaging). The transmission is a traditional five-speed automatic (W5A580) with a ZF electronic limited-slip differential, while permanent all-wheel drive is handled by a single-speed electronic proportioning transfer case (MP 3010). Properly equipped, the 2012 Grand Cherokee SRT8 can even tow 5,000 pounds, which is about average for this segment.
The Bilstein Adaptive Damping Suspension (ADS) is managed by Jeep's new Selec-Track system. In a nutshell, its electronics interact with multiple subsystems (stability control, adaptive damping, transmission shift points, transfer case proportioning, throttle control and cylinder deactivation) to automatically tune vehicle dynamics. However, drivers are also able to manually override the system and select one of five settings on the center console: Auto, Sport, Tow, Track and Snow.
As expected, Auto delivers the smoothest ride while Track is primarily designed for closed-course performance. Torque is variable under the Auto setting, but it is fixed at specific ratios while in the other modes (e.g., 50/50 front to rear in Snow mode and 35/65 in Sport and Track mode). Like the many lesser Grand Cherokee models, the SRT8 is also equipped with the Quadra-Trac system that uses sensors to determine and correct tire slip by transferring torque before it becomes a handling issue.
Those big brakes are sourced from Brembo. Painted bright red, the six-piston front calipers clamp on 15-inch front ventilated rotors while the four-piston rear calipers bite into 13.8-inch ventilated rotors. Standard wheels, meanwhile, are five-spoke 20-inch forged alloy units wearing 295/44ZR20 tires (all-season Pirelli Scorpion Verde rubber is standard, Pirelli P Zero three-season tires optional).
By Michael Harley
Posted Jul 25th 2011 11:57AM
We've just returned from flogging the all-new 2012 Jeep Grand Cherokee SRT8 on the main 2.5-mile road circuit at Willow Springs Motorsports Park in Southern California. This particular Jeep is nothing like your great-grandfather's ******, your cousin's lifted CJ or even your little sister's Liberty.
Lacking anything close to resembling a Trail Rated badge, this lowered, two-and-a-half ton monster packs a massive 6.4-liter Hemi under its hood, 20-inch forged alloys at each corner and an adaptive damping system to keep body movement in check. Even from a distance, it's hard to miss this four-door's oversized brakes, cannon exhaust pipes and intimidating body cladding. This Jeep looks mean, sounds aggressive and picks fights with sports cars instead of mountains.
But what is the point of the Grand Cherokee SRT8? Do its owners race it, or is this simply an exercise to antagonize cavalier Porsche Cayenne and BMW X5 drivers? What are the benefits – and drawbacks – to packing 470 horsepower in an SUV? Can this thing even tow?
We found answers to all of those questions and more, during our day on the track and long drive back to Los Angeles.
The Jeep Grand Cherokee SRT8 arrived on the scene in 2006 when the automaker dropped a 6.1-liter Hemi under the hood of the previous-generation (WK platform) body. Boasting 425 horsepower and a five-speed automatic transmission, the all-wheel-drive first-generation Grand Cherokee SRT8 was capable of sprinting to 60 miles per hour in the high four-second range and topping out at a redline-limited 170 mph. With twin center-mounted exhaust outlets and five-spoke alloy wheels, the monochromatic SUV had the looks to back up its bark.
Five years later, the fourth-generation Grand Cherokee rides on a new chassis (WK2 platform) shared with the 2012 Mercedes-Benz M-Class. After delivering its latest Trail Rated off-roader with competent but staid 3.6-liter V6 and 5.7-liter V8 powerplants, Jeep offering an SRT version of the Grand Cherokee was inevitable.
Launched at the 2011 New York Auto Show, the second-iteration SRT8 is a vast improvement over its predecessor. According to the automaker, on the tarmac, it's the best performing Jeep vehicle ever, with a 0-60 mph time of 4.8 seconds, a top speed of 160 mph and the ability to stop from 60 mph in just 116 feet.
As mentioned, the Grand Cherokee SRT8 version is unmistakable. Lowered one inch compared to the standard models, the SRT8 wears unique wheel flares, side cladding and a one-piece front fascia with new multi-function LED daytime running lights. The standard hood is replaced with a sculpted unit complete with functional ducts serving as heat extractors for the engine compartment. At the rear, there is a high-mounted liftgate spoiler to reduce drag and aerodynamic lift. A one-piece lower rear diffuser separates the new dual-sport exhaust pipes - while they looked wicked, its predecessor's twin center pipes were a nightmare for those who chose fit a trailer hitch.
The Grand Cherokee SRT8's interior features SRT-styled Nappa leather and suede upholstery, with sculpted bucked seats for the driver and front passenger. Carbon-fiber accents are splashed throughout the instrument panel and door trim, and an all-new heated leather-wrapped steering wheel arrives complete with transmission shift paddles. Jeep's center-mounted Electronic Vehicle Information Center (EVIC) also features performance pages – software that displays instant data about acceleration, horsepower, torque, wheel angle and so on.
Mechanically speaking, Jeep has made a lot of changes to transform its Moab-climbing Grand Cherokee into an asphalt-eating track star.
The hawkish hood hides a 6.4-liter Hemi V8. With a cast-iron block and aluminum-alloy heads, the 90-degree pushrod-operated 16-valve engine has a compression ratio of 10.9:1. Running on premium unleaded fuel, it is rated at 470 horsepower and 465 pound-feet of torque (down five pound-feet when compared to its other SRT8 siblings due to exhaust packaging). The transmission is a traditional five-speed automatic (W5A580) with a ZF electronic limited-slip differential, while permanent all-wheel drive is handled by a single-speed electronic proportioning transfer case (MP 3010). Properly equipped, the 2012 Grand Cherokee SRT8 can even tow 5,000 pounds, which is about average for this segment.
The Bilstein Adaptive Damping Suspension (ADS) is managed by Jeep's new Selec-Track system. In a nutshell, its electronics interact with multiple subsystems (stability control, adaptive damping, transmission shift points, transfer case proportioning, throttle control and cylinder deactivation) to automatically tune vehicle dynamics. However, drivers are also able to manually override the system and select one of five settings on the center console: Auto, Sport, Tow, Track and Snow.
As expected, Auto delivers the smoothest ride while Track is primarily designed for closed-course performance. Torque is variable under the Auto setting, but it is fixed at specific ratios while in the other modes (e.g., 50/50 front to rear in Snow mode and 35/65 in Sport and Track mode). Like the many lesser Grand Cherokee models, the SRT8 is also equipped with the Quadra-Trac system that uses sensors to determine and correct tire slip by transferring torque before it becomes a handling issue.
Those big brakes are sourced from Brembo. Painted bright red, the six-piston front calipers clamp on 15-inch front ventilated rotors while the four-piston rear calipers bite into 13.8-inch ventilated rotors. Standard wheels, meanwhile, are five-spoke 20-inch forged alloy units wearing 295/44ZR20 tires (all-season Pirelli Scorpion Verde rubber is standard, Pirelli P Zero three-season tires optional).
07-25-2011, 11:45 AM
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We picked up the Grand Cherokee SRT8 trackside, in the hot pits, when it was already running. Our first task was to wring a handful of laps out of it on Big Willow, the so-called "Fastest Road in the West," before driving it back to the Los Angeles Basin on speed-controlled roads.
Strapped into the front left seat with a closed-face helmet securely buckled under our chin, we were snug and comfortable in the cockpit. Despite the brain bucket, there was plenty of headroom and the seats were very supportive with excellent bolstering. Then a quick twist of our right wrist moved the Selec-Trac indicator to "Track." We followed that by a tap on the stability control button (located just below the driver's climate controls) to suppress some of the electronic nannies – the system is never completely off. After the track marshal's signal, we hit the accelerator and moved onto the hot track.
Full-throttle acceleration in a 470-horsepower all-wheel-drive vehicle is always exhilarating. Thrown hard against the seatbacks, we held the thick steering wheel straight as we accelerated towards Turn 1. Expecting a slight delay as the chassis reacted to the new angle of the front wheels, we turned in a bit early. Instead, and to our surprise, the SUV followed our commands immediately and we arced beautifully around the first corner without screaming tires or any drama from the stiff chassis.
Whether you like high-performance SUVs or not, it is amazing to experience just how well a good one can handle elevated speeds on a professional road racing circuit. The Grand Cherokee SRT8 weighs 5,150 pounds (the equivalent of a standard Porsche 911 with a Fiat 500 strapped to its roof), yet it hung with tenacity around the corners in pursuit of smaller vehicles on the track. It is impossible to defy the laws of physics, but the big Jeep sweats it out in an effort to do just that.
Massive sticky Pirelli tires on all four corners give the truck a huge contact patch, while its all-wheel-drive system delivers the grip of caterpillar tracks pulling out of the corners. It is a real hoot to stomp the pedal and hang on as the torque is distributed around the platform. While the rear-wheel-drive cars tip-toed gingerly on the tightest bends, those were the moments the Jeep SRT8 put down its power and shined.
The Jeep's brakes also impressed us, as they seemed oblivious to the amount of work they were doing. We found ourselves diving deeper and deeper into each corner, shaking our heads in amazement that the pedal wasn't getting softer with subsequent repetitions. To say they were un-Jeeplike is an understatement. To call them almost Porschelike would be a well-deserved compliment.
There is always something oddly demented about driving an SUV around a race circuit, but the memories remain vivid. This author's recollection says the Grand Cherokee SRT8 is the third SUV he's have truly enjoyed on the track – putting the new Jeep in prestigious company. Seemingly equally as agile as the BMW X5 M (5,368 pounds), the SRT8 is still down on both handling and power compared to the much lighter Porsche Cayenne Turbo (4,784 pounds). But remember, those two enemies will lighten your wallet far more than the flagship American.
After lunch and a quick photo shoot on the paddock, it was time to head back to Hollywood. The trip would take us 75 miles south as we followed major highways for most of the route. The Jeep was a whole different animal in this civilian environment. While our noggin was suffering from a severe case of helmet hair, our body remained comfortable thanks to cooled seats and dual-zone climate control. And, we can't fail to mention the audible pleasure of hearing static-free satellite radio tunes out of the new 7.3 Harmon Kardon Logic 7 surround sound system.
Power on the open road was strong, as one would expect. The five-speed automatic transmission was smooth under normal throttle applications, but shifts seem to be more delayed and abrupt the harder it was pressed – not to the level of annoyance, but it was noticeable. Steering is good (great steering wheel, by the way), wind noise is low and the SUV tracks well at highway speeds.
Our two gripes about the Grand Cherokee SRT8 are both directly related to its performance mission. Despite the new standard fuel saver technology and active valve exhaust system, both credited with a 13-percent improvement in highway fuel economy, the Jeep is thirsty (EPA fuel economy rating of 12 mpg city and 18 mpg highway). We also noticed a lot of road noise permeating the cabin at highway speeds. but neither issue would stop us from putting the SUV in our driveway.
So, what's the point of the Grand Cherokee SRT8?
Without question, it will do a magnificent job antagonizing the occasional Porsche Cayenne, BMW X5 and supercharged Range Rover at the stoplight - there's a bona fide muscle car hidden within. But more than that, the 2012 Grand Cherokee SRT8 is a benchmark example of American high-performance engineering. The SRT team at Chrysler Group LLC has packed the five-seater with innovative technology, both under the hood and within the passenger cabin. With decades of skill and knowledge behind them, these people have taken a very capable off-road vehicle and transformed it into an adept track star. While it may have lost its off-road aptitude and natural lust for dirt, it has gained immeasurably entertaining talents through SRT's metamorphosis.
07-25-2011, 08:04 PM
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awesome practicality, great power, fantastic build quality on the new platform......but it seriously looks like one shopping mall door ding along the side. It almost looks like they tried to take the scallop from the new Charger.
I like the interior, powertrain, and fit and finish with this model, but they nailed the looks on the last one, IMO.
I like the interior, powertrain, and fit and finish with this model, but they nailed the looks on the last one, IMO.
